This invention relates to balloon catheterization.
A balloon catheter is a device with an elongated shaft that carries an inflatable balloon. Typically, the shaft is delivered into a narrow body lumen with the balloon in a low profile deflated state. When the treatment site is reached, the balloon is inflated to its full diameter. After treatment is complete, the balloon is again deflated, hopefully to a small diameter profile, and the catheter is removed from the body. Inflation of the balloon may be effective to, for example, dilate the lumen, deliver a stent to the site, block the lumen, at least temporarily, stabilize the catheter, or deliver drugs to the lumen walls.
The invention relates to collapsing a balloon to a small profile during deflation by preventing tension in the catheter or balloon which might otherwise direct the balloon into a larger diameter collapsed profile, making it difficult to remove the catheter from the body. Tension in the catheter may be avoided by arranging at least one end of the balloon to slide with respect to the catheter. The invention is applicable to, for example, a relatively stiff, inelastic balloon that is preformed into a geometric cross-sectional shape with corners, such as a square balloon, for encouraging a particular collapsed configuration, e.g., three or more folded lobes.
In a first aspect, the invention features a balloon catheter with a flexible catheter body portion extending longitudinally, a spanning portion, and a tip region. The tip region is axially displacable with respect to the spanning portion between a retracted condition and an extended condition without biasing the spanning portion and tip region. The catheter also includes an inflatable balloon having a working portion and proximal and distal end portions. The proximal end portion is attached to the catheter body and the distal end portion is attached to the tip region. The working portion is preconditioned to form at least three lobes.
In another aspect, the invention features a balloon catheter with a flexible catheter body portion extending longitudinally from a region remaining outside the body to an end region positioned inside the body, a spanning portion extending through the flexible body portion from the region remaining outside the body and beyond the end region, and a tip region in sliding telescoping relationship with the spanning region between a retracted condition and an extended condition. An inflatable balloon is provided having a proximal and distal end portion. The distal end portion is attached to the tip region.
In another aspect, the invention features a method, including delivering a balloon catheter into the body, the balloon catheter including a catheter body extending longitudinally, a tip region, and an inflatable balloon. The balloon has proximal and distal end portions. The proximal end portion is attached to the flexible catheter body portion and the distal end portion is attached to the tip region. The method also includes inflating the balloon, during which the tip region is axially displaced with respect to the catheter body to a retracted condition without biasing the flexible catheter body and tip region.
Embodiments may include one or more of the following. The spanning portion is axially fixed relative to the catheter body portion. The tip region is an element concentrically arranged with respect to the spanning portion. The tip region includes a tubular element concentrically about the spanning portion. The tip is axially slidable relative to the spanning portion. The tip is arranged concentrically over a distal portion of the spanning portion. The spanning portion is a solid wire-member. The spanning portion is fixed to the flexible body portion. The spanning portion is a tubular member.
Embodiments may also include one or more of the following. The catheter body and tip region include lumens arranged to pass a guidewire through the balloon and beyond the tip member. The catheter spanning portion includes a lumen for passage of the guidewire. The tip region is articulated by a collapsible region. The tip region is in telescoping relationship.
Embodiments may also include one or more of the following. A strand element is attached between the catheter and the tip region. The strand element is in a slack condition, free of substantial bias when the tip region is in the retracted condition or extended condition. The tip member and catheter body have complementary mating structure. The tip member and catheter body have bayonet fitting structure. The catheter body has a spanning portion, spanning the interior of the balloon, the spanning portion being a continuous extension of the flexible catheter body portion. The catheter body, spanning portion, and tip-region include lumens for passage of the guidewire. The balloon is made of a substantially inelastic material. The balloon is made of PET. The balloon is inflated to open an obstructed lumen. The catheter is placed over a guidewire.
Implementations of the invention may have certain advantages. For example, reliable collapse of the balloon to small diameter makes it easier to withdraw the catheter from the body, particularly in cases where the catheter is drawn into another catheter, such as an introducer catheter or an endoscope.
Still further aspects, features, and advantages follow.
We first briefly describe the drawings.